1. Field
Embodiments of the present invention relate to sensing temperatures on integrated circuits and, in particular, to a thermal detection circuit with adjustable calibration settings.
2. Background
Integrated circuits (ICs) generate heat when powered by an electric source such as a power supply. ICs are generally susceptible to overheating which may cause the IC or the device in which the IC is employed to fail, to malfunction, to be uncomfortable for the user to handle, or to otherwise diminish the utility of the IC or the device. Controlling excess heating in ICs is becoming a more serious problem as more powerful and more complex ICs are packaged in smaller and lighter IC packages. For example, computers are steadily increasing the amount and density of memory within the microprocessor, in the system memory and on various add-in cards. Increases in clock speeds and device activity combined with increases in the number and density of devices in one chip further increase the heating of the devices.
Thermal management is used to prevent the IC and the device in which the IC is employed from overheating. A variety of thermal management devices and techniques have been employed to attempt to prevent ICs from overheating. These devices include fans, fins, and liquid cooling pipes that draw heat away from the IC to a radiator. Some thermal management devices adjust the duty cycle by, for example, reducing clock speeds or input and output rates or voltages to reduce the temperature. All of these approaches have some negative effect. The effect may be in cost, size, noise, power consumption or reduced performance.
When the temperature is sensed directly, then fans or duty cycle adjustments may be applied in response to the sensed temperature. As a result, some of the negative impacts may be reduced. If the IC is running cool, then fans, coolers or duty cycle adjustments can be turned off, saving power and increasing performance. The more accurate the temperature measurement, the more accurate the use of the thermal management devices may be. This allows, for example, the fan to be turned on only when absolutely necessary, reducing noise and power consumption. The more accurate the thermal sensor, the more accurate the control may be.